Results 1 to 7 of 7

Math Help - limits with some fractions

  1. #1
    Junior Member
    Joined
    Mar 2013
    From
    moon
    Posts
    56

    Question limits with some fractions

    hi
    this time i have a question about this problem

    limits with some fractions-1.gif

    what is the correct way to solve this kind of problem?
    do i get an undefined expression with oo * 0 ?
    or do i first simplify the right-hand expression and then multiply the two sides and check what happens when x approaches oo ? the limit is oo.
    or do i first multiply the two sides and i get the limit to be 11.1?

    thanks for the clarification.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Nov 2011
    From
    Crna Gora
    Posts
    420
    Thanks
    64

    Re: limits with some fractions

    Quote Originally Posted by ryu1 View Post
    hi
    this time i have a question about this problem

    Click image for larger version. 

Name:	1.gif 
Views:	5 
Size:	1.5 KB 
ID:	27640

    what is the correct way to solve this kind of problem?
    do i get an undefined expression with oo * 0 ?
    or do i first simplify the right-hand expression and then multiply the two sides and check what happens when x approaches oo ? the limit is oo.
    or do i first multiply the two sides and i get the limit to be 11.1?

    thanks for the clarification.
    First simplify the right-hand expression and then multiply the two sides . After that divide both numerator and denominator by x^2
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Mar 2013
    From
    moon
    Posts
    56

    Re: limits with some fractions

    Quote Originally Posted by princeps View Post
    First simplify the right-hand expression and then multiply the two sides . After that divide both numerator and denominator by x^2
    but if i simplified the hand hand side im left with

    (3x-2)(74x+125)

    there isnt a denominator here, did i made a mistake?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor Siron's Avatar
    Joined
    Jul 2011
    From
    Norway
    Posts
    1,250
    Thanks
    20

    Re: limits with some fractions

    Where's the denominator? Note that
    \frac{6}{4x+7}+\frac{11}{5x+8} = \frac{74x+125}{(4x+7)(5x+8)} = \frac{74x+125}{20x^2+62x+56}

    Can you compute the limit now?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Mar 2013
    From
    moon
    Posts
    56

    Re: limits with some fractions

    yes then i multiply the numerator by 3x-2 (or just the 74x with the 3x)
    I get 222x^2
    I divide that by 20x^2
    it get me to 11.1 thats the limit?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor Siron's Avatar
    Joined
    Jul 2011
    From
    Norway
    Posts
    1,250
    Thanks
    20

    Re: limits with some fractions

    Quote Originally Posted by ryu1 View Post
    yes then i multiply the numerator by 3x-2 (or just the 74x with the 3x)
    I get 222x^2
    I divide that by 20x^2
    it get me to 11.1 thats the limit?
    That is correct!
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Junior Member
    Joined
    Mar 2013
    From
    moon
    Posts
    56

    Re: limits with some fractions

    Alright!

    I needed a refresher on the simplification of fractions with variables there

    Thanks!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. fractions witin fractions
    Posted in the Algebra Forum
    Replies: 3
    Last Post: July 18th 2012, 01:10 PM
  2. Replies: 0
    Last Post: April 28th 2010, 10:53 AM
  3. Limits with fractions
    Posted in the Pre-Calculus Forum
    Replies: 4
    Last Post: April 12th 2010, 10:58 AM
  4. limits with fractions (x in denominator)
    Posted in the Calculus Forum
    Replies: 4
    Last Post: September 13th 2009, 08:21 AM
  5. summation limits in fractions
    Posted in the LaTeX Help Forum
    Replies: 13
    Last Post: November 2nd 2007, 09:02 AM

Search Tags


/mathhelpforum @mathhelpforum